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Courtney A. Hardy, MD
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Mark Twite, MD, BCh
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Stuart R. Hall, MD
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INSIDE

President's Message

Letter from the Editor


STS-CCAS Database Update

Brief Update: Status of Pediatric Heart Transplantation

Pediatric Heart Transplant in Canada

Pediatric Heart Transplant in the UK

LITERATURE REVIEWS

The Registry of the International Society for Heart and Lung Transplantation:  Fifteenth Pediatric Heart Transplantation Report – 2012

 

 

 

2013 CCAS Annual Meeting Summary

By Greg Latham, MD & Jeremy Geiduschek, MD
Department of Anesthesiology and Pain Medicine
Seattle Children’s Hospital
University of Washington School of Medicine
Seattle, WA

The 2013 Annual Meeting of the CCAS was convened on March 14, 2013 at the Red Rock Casino in Las Vegas, Nevada. There were over 200 in attendance participating in a fantastic program. The meeting kicked off with a welcome by current CCAS President Dr. Helen Holtby (Hospital for Sick Children, Toronto, ON) and an outline of the activities for the day by Program Chair, Dr. Jumbo Williams (Lucille Packard Children’s Hospital, Stanford CA).

Session I: Basic Science & Practical Application: Cardiopulmonary Bypass

Moderator Dr. Scott Walker (Riley Hospital for Children, Indianapolis, IN) opened the first session. Throughout the day, the audience was peppered with questions for which responses could be collated and displayed for all to see. This provided tremendous insight into the demographics and practice patterns of the audience.

A common theme for the day was how little we fully comprehend about the effects and outcomes of cardiopulmonary bypass (CPB). 42% of the audience felt they knew “something” about CPB and another 42% stated they could not identify all the components of the bypass machine. This segued into the first lecture by Dr. James DiNardo (Boston Children’s Hospital and Past-President of the CCAS). His whirlwind discussion of “What’s So Bad About Cardiopulmonary Bypass- We Do It Every Day?” started with a series of questions to the audience in anticipation of each of the themes of his talk.

Theme 1: Heparin, thrombin and inflammation. 83% of the audience administers the first does of unfractionated heparin (UFH) based on weight. 28% determine subsequent doses based on weight and 78% based on results of ACT or heparin level measurement. 76% have the cardiotomy suction drain directly to the CPB reservoir. The molecular regulation of coagulation, fibrinolysis and inflammation are inextricably linked. Dr. DiNardo reviewed findings from key experiments from a myriad of research groups. Thrombin is a key player in coagulation and inflammation via interaction with protease-activated receptors located on leukocytes, smooth muscle, endothelial cells and platelets. Thrombin is everywhere and suppression of thrombin formation with the use of UFH is not complete.

Dr. DiNardo showed evidence that ACT measurement is a surrogate for heparin levels and is hit or miss. Also, ACT does not accurately assess the degree of suppression of thrombin formation. Contrary to popular perception, blood contact with the surface of the CPB circuit is not the prime generator of thrombin during surgical repair of congenital heart disease. It is the use of cardiotomy suction.

Did you ever wonder why patients on ECMO (with a significantly greater foreign surface area size to patient size ratio compared to CPB) are managed with ACT’s much less than the typical 400-500 seconds for CPB? The ECMO circuit is not “contaminated” with cardiotomy suction. Following release of aortic cross clamp, the cardiotomy suction gathers byproducts from the surgical wound. Thrombin and clot generated in the surgical wound has a very different thrombolysis profile than clot generated primarily from foreign surface contact. Clot generated by tissue factor and factor VIIa (as would be collected in cardiotomy suction) is less resistant to fibrinolysis than contact activated clot. Plasmin has a major role in both fibrinolysis and in regulating inflammation. There is perhaps a link then with excess fibrinolysis that can occur when cardiotomy suction is utilized with inflammation, though studies have failed to yet show that measures of inflammatory markers correlate with outcomes.

Theme 2: Inattention to hemolysis. When asked how often rose-colored urine following CPB is witnessed the audience responded 5% never, 70% occasional, and 25% often. 56% administer steroids to every CPB patient, 36% depending on circumstances and 8% not at all. Plasma free hemoglobin comes from transfusion of aged RBC’s and from use of cardiotomy suction. It is a scavenger of nitric oxide and results in vasoconstriction and may be implicated in end-organ injury. Steroid administration has been shown to increase haptoglobin levels. Haptoglobin is a scavenger of plasma free hemoglobin.

Theme 3: Inattention to DO2 and the microcirculation during CPB. Asked how often a lactate > 3mmol/L is encountered, 3% responded never, 56% occasionally, 34% often and 7% always. Dr. DiNardo reviewed several studies demonstrating that following MAP, CPB flow rates, SVO2 and NIRS are not of themselves adequate to fully assess adequacy of oxygen delivery during CPB. There is some evidence that following VCO2 may improve decision making to optimize DO2. There is good evidence that pulsatile flow is advantageous. There is also on the horizon new technologies that perhaps will provide real time windows into the microcirculation.

Dr. DiNardo ended his talk with a very succinct summary:

  1. Thrombin generation is poorly controlled on bypass.
  2. DO2 on bypass is inadequate.
  3. We have a very poor understanding of blood flow in the microcirculation during CPB.

Dr. Colleen Gruenwald (Hospital for Sick Children, Toronto ON) delivered the next talk titled: “Cardiopulmonary Bypass: Current State-of-the-Art & New Developments.” The talk initiated with a series of questions to the audience assessing knowledge.

Everyone was on the same page in knowing that infants following CPB may have bleeding due to hemodilution, an immature coagulation system and extensive complex surgery. All were aware that early age at operation, low pre-op hemoglobin concentration and a longer CPB run were predictors of the need for RBC transfusion. Everyone agreed that the medical literature has outcome evidence to support transfusion of RBC’s stored less than 14 days.

However, only 66% appreciated the statement “evidence supports a target hct of 21% for infant heart surgery” as FALSE. Dr. Gruenwald put forth the challenge that bloodless infant cardiac surgery is feasible and desirable. She discussed the risks of transfusion as well as no clear efficacy in RBC transfusion reducing morbidity and mortality. Also, evidence was presented demonstrating that the duration of RBC storage prior to transfusion is an independent risk factor for poorer outcomes.

How then to move towards a bloodless prime and eliminate RBC transfusion? Efforts need to focus on the essentials of multi-disciplinary teamwork and continually improving technologies and techniques of CPB. This means smaller components of the bypass circuit held closer to the patient. It will mean optimizing flow in the setting of acute normovolemic hemodilution. Vacuum assisted drainage, venous antegrade prime and retrograde arterial prime may become part of the “going on pump” routine. Recovery of RBC’s from the circuit following bypass may also be necessary.

The Berlin Heart Centre has been pioneering some of this work, which was reviewed by Dr. Gruenwald. They have a pump prime of 100 mL, use flow rates up to 3L/min/m2 and have lower transfusion triggers (HgB 7 g/dl during CPB) than many other practices. In their practice they have neonates who undergo arterial switch operation and do not receive RBC transfusions during their hospitalization (6 of 23 in two published series). Determining what is the safest lower limit for HgB/HCT is also not clear. There is a linear correlation between psychomotor development and HCT from 15-24% when low flow, 18°C, CPB is used. The audience was cautioned to avoid as a routine to allow the hct below 25%.

Dr Gruenwald ended by summarizing:

  1. “Optimal” perfusion is yet to be defined, including triggers for transfusion.
  2. We should advocate using only the freshest blood.
  3. We need to continually challenge ourselves to encourage technology development and innovation to make smaller bypass circuits possible and further decrease the need for transfusion during CPB for neonatal cardiac surgery.

The session concluded with Q & A. An audience member asked if the CCAS should advocate that fresh whole blood be available? All agreed that there is evidence to advocate for the “freshest” blood available. A panel member cautioned that creating a one-off workaround in a blood banking system not used to preparing fresh whole blood may result in a clerical error and possible transfusion error.

Each panel member described the criteria used at each of their centers. At Riley Children’s, blood stored < 5 days is used for patients < 17kg. At Toronto Hospital for Sick Children, RBC’s < 5 days old are used for patients < 2 months old. For all other patients RBC’s < 14 days old are used. At Boston Children’s RBC’s less than one week old are used on everyone.

When asked about monitoring heparin effect, Dr. DiNardo recommended using a heparin management system as opposed to following ACT. Dr. Gruenwald seconded this recommendation stating that there are studies in infants showing shorter duration of mechanical ventilation, shorter ICU length of stay and less transfusion.

Session II: Electrophysiology (EP) and Rhythm Disturbances

Dr. Susan Staudt (Children’s Hospital of Wisconsin, Milwaukee WI) opened the session by asking the audience several questions. Regarding provision of anesthesia for EP cases: 49% have the service provided by the pediatric CV anesthesia group, 24% are mixed depending on patient complexity, 26% have any member of the group. 71% most commonly utilize GA with either an ETT or LMA, 22% use deep sedation (as a bias against using a volatile agent) and 7% routinely use conscious or moderate sedation.

In the heart room, 75% of the audience responded that they are responsible for making temporary pacemaker setting adjustments, for 15% it is the CV surgeon and 4% the cardiologist. When given a choice between managing low cardiac output vs. a “bad” arrhythmia, 22% preferred dealing with a rhythm, 56% preferred low cardiac output and 22% were grateful for bypass and cardiologists.

Dr. Johanna Schwarzenberger’s (UCLA) talk on “EP Studies: Does Anesthetic Technique Matter?” provided an overview of the types of rhythm disturbances that are managed in an EP lab and their etiologies. Most busy EP labs see pediatric patients with slow and fast rhythm disturbances, with the latter being the most common.

The primary mechanisms for arrhythmogenesis are reentry, abnormal automaticity or triggered activity. Reentrant tachyarrhythmias are the most common in teenagers. WPW is being diagnosed more frequently due to increased screening. A small subset of patients with WPW is at increased risk for sudden cardiac death. This includes patients with WPW and atrial fibrillation or prior syncope but may also include WPW patients who are asymptomatic. Hence, it is common to have adolescents with WPW present to the EP lab for mapping and risk stratification.

A brief overview of the cardiac mapping procedure was provided. Following venous access (RA, coronary sinus, LA and RV), surface and intracardiac ECG’s’ are compared. Conduction times between regions of the heart are measured. Pacing catheters with or without pharmacologic (i.e. isuprel) assistance can be used for tachycardia stimulation (as well as for back-up or overdrive pacing to treat complications). Ablation catheters (radiofrequency, ultrasound, cryo) can be used to scar regions of abnormal conduction and are used to treat a-flutter, WPW, AVNRT, a-fib, v-tach, and therapeutic AV node ablation. Procedural risks include: AV block, chamber perforation, coronary artery thermal injury, thromboembolism (especially w/ trans-septal catheter placement), radiation exposure, non-detection of recurrence after presumed ablation, and risks from anesthesia or sedation.

Procedure failures have been attributed to: difficult to access or unexpected aberrant pathway location, technical issues, operator factors, and “too much sedation or anesthesia.” The remainder of the talk focused on the effects of anesthetic agents on the cardiac conduction system and a review of studies completed examining anesthetic choice for EP lab procedures. All anesthetics will alter EP measured parameters. Volatile agents can prolong the QTc, have varying effects on AV node and His-Purkinje conduction and can enhance automaticity of secondary atrial pacemakers. Opiates and muscle relaxants may alter autonomic nervous system tone. Dexmetetomidine can slow sinus node and AVN function.

Results with propofol are mixed, with some studies reporting prolonged atrial and AV conduction and others showing no alteration. In short---there is no magic bullet; therefore, anesthetic technique will require an individualized approach depending on patient age, maturity, co-existing disease, and specific EP study requirements.

Comments from the audience focused on GA vs. sedation and that movement during the procedure can force the electrophysiologist to have to remap pathways tilting the choice of the anesthesiologist towards doing a GA.

Dr. James Perry (Rady Children’s Hospital, San Diego CA) was unable to deliver his lecture titled: “Management of Perioperative Arrhythmias” due to a flight cancellation. The reader is referred to his very through handout in the course syllabus.

Session III: Insights From Recent Literature: Three Favorite Papers

Dr. Nina Guzetta (Children’s Healthcare of Atlanta) asked each of the panel members to select and discuss a “favorite” article in the recent medical literature. Dr. Annette Davis (Alder Hey Children’s Healthcare, Liverpool UK) led off by discussing Vogt W, Laer S. Prevention of pediatric low cardiac output syndrome: results from the European survey EuLoCOS-Paed. Pediatr Anesth 2011; vol 21 (12):1176-1184. The manuscript details a survey study done of European medical centers where children undergo open heart surgery.

The results and discussion center around a subset of questions regarding preventive drug therapy for post-operative low cardiac output syndrome. 90 hospitals responded (72%). Of these 78% utilize preventive drug therapy (63% of the total group to “at risk” patients and 14% to all patients). Milrinone is the most commonly used medication either alone or in combination with dopamine, epinephrine, dobutamine or levosimendan. Dr. Davis commented on the marked variability in drug regimens, lack of consistent definition of patients considered “at risk” and the variation in practices based on a very limited amount of evidence in the medical literature—all point to the need for focused clinical studies in the future.

Dr. Victor Baum (University of Virginia, Charlottesville VA) selected Augus M, Steil G, Wypij D et. al. Tight glycemic control versus standard care after pediatric cardiac surgery. NEJM 2012; 367:1208-19. He described how he determines if an article rises up to the status as a “favorite.” Does the paper address a problem that is important? Does it involve a subject that affects many practitioners? Does it address a contentious issue? Can the findings be expressed simply? Is the conclusion clear?

Dr. Baum reviewed several key articles on the subject of tight perioperative glucose control demonstrating conflicting results. When asked of the audience, 50% felt glucose management during cardiac surgery is important and 50% did not.

The study by Augus et. al. involved 980 pediatric cardiac surgery patients treated at either Boston Children’s or the University of Michigan CS Mott Children’s Hospital. There was no difference in primary outcome (health care-associated infections) or secondary outcomes (mortality, CICU length of stay, organ failure or hypoglycemia) between the groups with tight glycemic control (glucose 80-110 mg/dL) vs. standard care. Dr. Baum concluded by stating the article met the majority of his criteria to be a favorite paper but did lack one essential quality to make it a perfect paper—he was not a co-author.

The final paper of the session was presented by Dr. Kenneth Brady (Texas Children’s Hospital, Houston TX). He selected Chestnut R, Temkin N, Carney N, et. al. A trial of intracranial-pressure monitoring in traumatic brain injury. NEJM 2012; 367:2471-81. The manuscript concerns a very controversial study that was conducted in Ecuador and Bolivia by research teams from the US and Argentina.

In the US, the use of an ICP monitor in the setting of acute traumatic brain injury was considered a “guideline level recommendation.” This is not based on evidence from randomized clinical trials (RCT) but from consensus of experts in the field. This study is an attempt to obtain randomized trial data to support or refute the efficacy of ICP monitor utilization in improving outcome.

The study demonstrated no difference between groups receiving ICP monitors and those managed based on imaging and clinical findings. Dr. Brady cautions the audience that doing an RCT for monitor utilization is very different than comparing two interventions, likening this “evidence” to very dangerous Kool-Aid. He poses the question: “which of the monitors that we use in anesthesiology have been shown to improve patient outcome in an RCT and are we prepared to stop using the ones that have not?”--A very important question for the audience to ponder during lunch, which was next on the agenda.

Session IV: CCAS Update from the Leadership - Past, Present and Future

Dr. Dean Andropoulos (Texas Children’s Hospital, Houston TX), Dr. James DiNardo (Children’s Hospital Boston), and Dr. Helen Holtby (Hospital for Sick Children, Toronto ON) presented the past, present, and future of the CCAS and its annual meetings during a lunchtime session. Dr. Andropoulos, who helped found CCAS, discussed the history of CCAS. In 2004, 29 founding departments donated $5000 to start the CCAS.

With strong support from the Society for Pediatric Anesthesia, the CCAS was formally founded on December 7, 2005. The mission statement from 2004 persists today: education, collaboration, coordination, research, database, training and advocacy.

The accomplishments of the society of which he is particularly proud include:

  1. annual meetings with strong attendance,
  2. merging of the CCAS database with the Society of Thoracic Surgery (STS) database and 1,000s of submitted cases, and
  3. the formation of training guidelines for pediatric cardiac anesthesia, including a 12 month curriculum of training for the pediatric cardiac anesthesia fellowships.

Dr. DiNardo, immediate past-president of CCAS, expressed how excited he is about the present and future of CCAS. He pointed out that a Factor VIIa review article has been written, stemming from discussions from last year’s meeting and the collaboration of CCAS members.

Going forward, he stated that there are two items that he feels require specific attention:

  1. all programs that are training pediatric cardiac anesthesia fellows need to collaborate so that we can learn from the strengths of various programs and ensure we are appropriately training the fellows, and
  2. someone needs to step up to become a leader in the management of adult congenital heart disease patients, and he feels that pediatric cardiac anesthesiologists need to take the lead, not adult anesthesiologists.

Dr. DiNardo closed with thanking everyone for their support over the past two years. Dr. Holtby discussed her vision to form a “from fetal to fatal” model of care of persons with congenital heart disease, providing perioperative expertise through every age of life. She then took the opportunity to seek the CCAS membership’s guidance for how to move CCAS forward.

She asked, “Do we want to be attributed as a national committee or should we forge relationships with international societies and become an international society?” and then presented the following questions for audience participation:

Dr. Holtby closed by expressing her gratitude to Dean Andropoulos for all of his time and dedication to get CCAS up and running. Drs. Victor Baum and James DiNardo were presented with awards for outstanding service to the Society.

Session V: Posters: Selected Oral Presentations

Dr. Mark Twite (Children’s Hospital of Colorado, Denver CO) moderated the session, explaining that 55 abstracts were received and reviewed. The top 18 abstracts were accepted for the evening poster presentation session, and the top three were chosen for oral presentations.

Dr. Machovec (Duke Children’s Hospital, Durham NC) presented her abstract on “Hemostasis Management System to Monitor Anticoagulation in Infants and Toddlers on Cardiopulmonary Bypass”. Traditionally, heparin anticoagulation is measured with ACT, but ACT overestimates anticoagulation in infants. The hypothesis of the study was that the Medtronic Hemostasis Management System (HMS) would result in reduced blood product usage and operating room time for infants undergoing cardiac surgery. HMS versus ACT management was compared in 58 infants in each group.

Their conclusion was that HMS is a cost-effective alternative to ACT monitoring for anticoagulation management of infants on CPB, leading to lower operating room time and lower blood product cost per patient.

The next abstract was presented by Dr. Deutsch (Children's National Medical Center, Washington DC), titled “Assessment for Spinal Cord Injury in Neonates Undergoing Surgical Repair of Coarctation of the Aorta”. Because infants are at risk of spinal cord ischemia during repair of coarctation, this study aimed to identify evidence of sub-clinical spinal cord injury during surgical repair of coarctation of the aorta.

Although postoperative MRI imaging did not demonstrate ischemic changes in the spinal cord, neurologic examination in two patients detected transient neuronal injury. Furthermore, somatosensory evoked potentials (SSEPs) during the operation demonstrated decreased amplitude during aortic cross clamp. Further studies are needed to investigate the significance of these findings and, if needed, develop interventions to provide intraoperative spinal cord protection.

Dr. Guzzetta (Children's Healthcare of Atlanta) presented the final abstract, titled “Augmentation of Thrombin Generation In Neonates Undergoing Cardiopulmonary Bypass”. The response to factor VIIa may not be optimal in the setting of coagulopathy immediately after bypass, and thrombin generation is necessary for clot formation.

The study compared in vitro the efficacies of factor VIIa and prothrombin complex concentrates (PCC) in improving thrombin generation in neonatal plasma after cardiopulmonary bypass. In conclusion, PCC increased thrombin generation more than factor VIIa when added to post-bypass blood samples of 10 neonates. Dr. Guzzetta warned, however, that the pro-thrombotic effects of PCC have yet to be delineated, and a randomized controlled trial is needed to find efficacy before advocating the use of PCC.

Session VI: Cardiac Care and Patient Safety - An Interactive Session

Dr. Jumbo Williams (Lucille Packard Children’s Hospital, Stanford CA) moderated the session and stated that this was the first patient safety session at a CCAS conference. Dr. David Vener (Texas Children’s Hospital, Houston TX) presented an overview and current update on the CCAS/STS database. There are 122 surgical programs providing congenital heart disease surgery in the U.S., and 101 are participating in the database. However, only 31 anesthesia programs are currently paying to participate. He stressed that more anesthesia programs are needed, and he invited interested programs to contact him anytime for more information.

Based on the 2010-2012 data sets, Dr. Vener presented the incidences and types of anesthetic adverse events. He concluded with a summary of the upcoming changes to the datasets due out in July 2013.

Dr. Calvin Kuan (Lucille Packard Children’s Hospital, Stanford CA), with assistance from Dr. Steve Tosone (Children’s Healthcare of Atlanta), presented the next session entitled “Teamwork: The Challenges.” An opening audience participation question asked “Have you received formal training in teamwork during medical education?” and the audience response was 50% “Yes” and 48% “No”.

Data show that personal skills and training alone are not enough to avoid adverse events; teamwork is necessary. Dr. Kuan introduced the concept of Crew Resource Management (CRM), which is a “a global approach for handling human limitations and behaviors in complex technological environments such as the operating room, by decreasing the probability of errors, trapping errors before they have operational consequence, and limiting the consequence of an error.”

The key components of CRM were reviewed and discussed in detail. The discussion was brilliantly summarized with two videos performed by healthcare providers at Stanford: a mock code without the use of CRM whereby patient safety was clearly compromised, followed by the same code managed with all of the principles of CRM.

Before the coffee break, Dr. Robert Friesen was given an award for recognition of service to CCAS

Session VII: Double Outlet Right Ventricle (DORV)

This excellent session was moderated by Dr. Wanda Miller-Hance (Texas Children’s Hospital, Houston TX) and was a thorough review of DORV for the anesthesiologist. Dr. Komal Kamra (cardiologist - Stanford University) presented the “Echocardiographic Features of DORV.” DORV is a ventriculoarterial connection whereby the “both great vessels arise entirely or predominantly (>50%) from the right ventricle.”

The physiologic presentation of DORV varies and is dependent on the location and size of the VSD, relationship of the VSD to the great arteries, degree of outflow tract obstruction, and any other associated congenital heart defects. Dr. Kamra systematically presented the myriad subtypes of DORV, discussing the incidence, anatomy, physiology, and echocardiographic views and findings of each. It was a thorough and informative presentation.

Dr. Victor Morell (Children’s Hospital of Pittsburgh) followed with a very informative session titled “Surgery for DORV.” He began with the historical perspective of the first attempted repair in 1957 and the refinement in technique to those used today. He discussed the surgical options for each of the subtypes of DORV, utilizing slides to demonstrate the pertinent anatomy that drives each decision.

Without surgical repair, 18% of children are alive in 15 years; with surgical repair, 60% of children are alive after 15 years, and the rate of re-operation is high, largely from right and left ventricular outflow tract obstruction. Although the Fontan procedure has been considered the procedure of choice for DORV and complex anatomy, some groups have challenged this and have discussed complex techniques. He presented multiple publications of complex single-stage complete repair as a newborn, each publication showing different DORV subtypes.

The take home message is that aggressive early repair is showing good results. He concluded his talk with discussion of the Nikkaidoh procedure for DORV with subpulmonic VSD and pulmonary stenosis. A current registry shows early respectable results.

Dr. James Spaeth (Cincinnati Children’s Hospital) presented “Perioperative Management of a DORV Case,” which was an excellent review for the anesthesiologist. He presented the case of a 5-day-old with Taussig Bing anomaly and severe aortic coarctation who presents for biventricular repair. After walking through the planned surgical repair, Dr. Spaeth thoroughly discussed the preoperative evaluation, anesthetic goals, and intraoperative management.

In particular, an understanding of oxygen delivery (DO2) and means to optimize it were discussed. Common problems after bypass were reviewed, including low cardiac output syndrome, arrhythmias, pulmonary hypertension, bleeding, and impaired pulmonary function. He concluded by discussing the causes of post-bypass hypotension, which include ventricular dysfunction, residual shunts, outflow tract obstruction, atrioventricular valve incompetence, coronary artery problems, hypovolemia, altered systemic vascular resistance, and pulmonary hypertension.

In the question and answer session that followed the three presentations, many participants took the opportunity to ask Dr. Morrell additional questions about surgical approach to various subtypes of DORV.

Session VIII: Posters: Viewing and Discussion

With refreshments served, attendance was excellent for the evening poster session. All abstracts are available online on the CCAS website, and the reader is encouraged to explore these 18 excellent abstracts.

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